Refrigerating apparatus



y 1, 1930. H. B. HULL 1,768,602

REFRIGERATING APPARATUS Filed April. :50. 1928 Patented July 1, 1930 IUNITEDTSTATES PATENT OFFICE WY 3. HUIJ4, OI DAYTON, OHIO, ASSIGNOB TO IBIGEDAIBE CORPORATION, 01'

DAYTON, OHIO, A CORPORATION OF DELAWARE BE'If'B-IGIBATING APPARATUS Application fled April :0,

This invention relates to improvements in v refrigerating apparatus and more particularly the means used for controlling the operation of mechanical'refrigerators.

It is' an object of the invention to provide means for operating the refrigerant circulating apparatus of a refrigerating system in such a'manner as to modif durin certain eriods the action of the sa et devices used or protecting the apparatus uring normal operation of the same.

With this object in view the invention contemplates providing means for automatically. causing the load normally borne by the regular safety device of the electrical circuit of the system to be distributed and carried bya plurality of such devices during the occurrence of a transient overload and to restore the circuit automatically to the normal control of the regular safety device when the transient overload is dissipated. It is a further object to arrange the devices carrying the overload in such a manner that prolonged overloading will cause them to operate to protect the system by breaking the circuit.

It is still another object of the invention to utilize a single means for controlling the safety device and also revent overloading of the compressor particularly during the startin operation.

Furt er objects. and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawing, wherein a preferred form of the present invention is clearly shown.

In the drawing:

There is shown a diagrammatic representation of a refrigerating system operated by a compressor and an electric motor and provided with the improved circuit protecting arrangement of the invention.

In the operation of refrigeratlng apparatus of the compressor-condenser-expander t pe, considerable pressure is stored up in tlie system, particularly after a period of idleness which pressure must be overcome by the compressor at the starting of the p p g p ation. This pressure resisttion provided, that is, thecapacit 1928. Serial N0. 278,854.

ance imposes a heavy load upon the motor dr vin the compressor. The electrical circult o the motor is provided with safety devices such as circuit-breakers, fuses or the like which prevent burningjout of the motor during stalling of the same by heavy overloads or the like. Normally the amount of protecof the fuses, etc., must not exceed a definite limit, usually rescribed by local regulations. If heavier uses are inserted into the motor circuit than are permitted by the re lations, the degree of protection is reduce However, in the operation of a refrigerator it requires only a few seconds of o eration or at most only a few revolutions o the compressor to reduce the pressure load after which the apparatus is able to function normally.

By means of the present invention means are provided for automatically connecting extra safety devices into the motor circuit during the beginning of the pumping operation so as to permittransient operation at a-higher cut-out limit and providing means for restoring the circuit to the normal control of the regular safety device after the apparatus has attained normal operation, the additional cut-out point or limit so obtained being designed to break the motor circuit if such abnormal load is prolonged beyond a definite limit. This is accomplished by means of a valve which not only reduces the pressure load on the compressor but also operates a fuse-controlling circuit in response to the starting load of the apparatus so as to insert an auxiliary safety device into the motor circuit.

Referring in detail to the drawing, the refrigerating apparatus shown for illustrating the preferred embodiment of the invention comprises a compressor 10 operated by a motor 11. The compressor forces refrigerant such as sulphur dioxide through pipe 12 into a condenser 13 wherein the refrigerant is condensed and collected in a receiver 14. From the receiver 14 the refrigerant passes b pipe 15 through an expansion valve 16 and into the cooling coils 17 of a refrigerating element where it performs its rener. The operation of the expansion valve may be modified by a suitable thermostatic device 18.- From the cooling coil 17 the vaporized refrigerant passes by means of pipe 19 back to the compressor. The thermostatic device is diagrammatically represented by 20 and is disposed so as to be responsive to the temperatures in the s ace refrigerated by the-cooling coils 17. his device is. used to actuate, as by means of a diaphragm 21 or the like, a circuit-makingand-breaking switch .22. This switch is shown in its motor operating position by the heavy lines and contacts 23 and 24 and in its non-operative position by the dotted lines 25. Normally the pipe 19 is connected directly to the crankcase 26 of the compressor 10 and when in operation only one safety. device 27 is used. However, duringstarting the automatic means of the invention serves automatically to insert anadditional safety device into the motor circuit, this device being indicated by 28. This operation is effected by passing the refrigerant from pi e 19 into a special circuit controlling valve system hereinafter described. This a valve comprises a casing 29' separated into an upper chamber 30 and a lower chamber 31 by means of a separatory wall 32. The separatory wall has a valve seat 33 against which operates a valve head 34 normally held out of engagement with the seat by a spring 35 disposed in a recess within the valve seat. The valve head 34 is carried by a rod 36 which in turn is fastened to the head 37 of a diaphragm or flexible bellows 38. After thecompressor has been idle for some time the pressure within the evaporator 17, pipe 19, chamber 30 and 31, pi .42 and crankcase 26 is relatively high an this pressure acting in the flexible diaphra or bellows 38 will expand the same an thus force the valve head 34 against the seat 33 tending to obstruct flow of gaseous refri erant into the comprexor. As the flexib e diaphragm which carries the valve expands it moves contact. 39 upwardly and forces the same into contact with terminal 40 to complete the circuit and insert the safety device 28 in the motor circuit. 7

A small bleeder passageway 41 is provided in the separatory wall 32-so that a limited amount of refrigerant will be withdrawn from the evaporator when the compressor starts. The amount of refrigerant delivered to the compressor will be metered so as to prevent overloading.

When the refrigeratin system is thus I idle, the expansion of the exible chamber 38 maintains the contacts 40 and 39 in closed or contacting position. In this position the auxiliary or additional safety device is kept in the circuit in arallel with the re ar safety device oft e electric circuit 0 the motor. After the compressor has operated valve- 34: to open thus separatin 'sure side, means'for actuatin for a short period, say a few revolutions refrigerant in sufficient amount will be withdrawn from the low pressure side so that the pressure is reduced sufliciently to permit the contacts 40 and 39 and breaking the circuit'throu h the auxiliary safety device. After this, t e re lar safety device of the motor circuit is su cient to protect the same from protracted overloads caused bystalling and the like.

By means of the present invention anarrangement is rovided for taking care of transient over oads occurring during the startin operation of refrigerating apparatus an for restoring the system to the control of the regular safety device used, for normal operation, without lowering the safety factor of the system.

While the form of embodiment of the invention as herein disclosed, constitutes a preferred form, it is to be understood that other forms might be adopted, all coming within the scope of the claims which follow. What is claimed is as follows:

1. A refrigera system having a high pressure side and a ow pressure side, a compressor for compressing refrigerant received from the low pressure side and supplying it at an increased pressure to said high pressaid compressor, a control circuit for t e actuating means, said control circuit includin a plurality of safety devices, means or controlhng one of said safety devices and arranged to control the amount of charge taken in by said compressor.

2. In a refrigeratin system in combination, a refrigerating e ement, a compressor for supfplying refrigerant to said element, a motor or driving said compressor, a safety device in the motor circuit, an auxiliary safety device for said motor circuit, and means operated by the pressure of refrigerant within said system for inserting sai auxiliary safety device into the motor circuit.

3. In a refrigeratin system in combination, a refrigerating e ement, a compressor for circulating refri rant through said element, a motor for riving said compressor a safety device for protecting the circuit of said motor from overload, an auxilia safety device, and means operated by the pressure of the refrigerant inrsaid m or connecting said auxiliary safety evice into the motor circuit during starting of the system.

4. In a refrigeratin system in combination, a refrigerating e ement, a compressor for circulating refrigerant through said element, a motor for driving said compressor, means responsive to overloads for rendering said motor inoperative, said means comprising a plurality of safety devices, one of said devices being permanently connected into said circuit and adapted to render saidmotor inoperative upon occurrence of a redetermined overload and an auxiliary sa ety device adapted to cooperate with said firstnamed-safety device for permitting transient operation of said compressor for a predetermined time at a predetermined overload and means responsive to pressure of the refrigerant within said system for inserting said auxiliary safety device into the motor circuit. I

5. In a refrigerating system in combination, a refrigeratin element, a compressor for circulating refrigerant through said ele-- ment, a motor for driving said compressor,

a valve responsive to pressure of refrigerant within said system, a safety device for said motor circuit adapted to render said circuit inoperative durin overload and an auxiliary safety device a apted to be placed into the motor circuit by the operation of said valve, said auxiliary safety devicebeing adapted to cooperate with said firstnamed safety device to permit operation of said motor for 'a predetermined overload period.

6. In a refrigerating system, in combination a refrigerant circuit including circulatin means, a motor for driving the circulating means, a power circuit for the motor, means for interrupting the power circuit, and means res onsive to the pressure of the refrigerant or controlling the capacity of the circuit interrupting means.

7. In a refrigerating system, in combination a refrigerant circuit including circulating means, a motor for driving the circulating means, a power circuit for the motor, means for interrupting the power circuit, and means responsive to the condition of the refrigerant circuit for controlling the capacity of the circuit interrupting means.

8. In a refrigerating system, in combina- I tion a refrigerant circuit including circulating means, a motor for driving the circulat ing'means, a power circuit for the motor, means for interrupting the power circuit, and means responsive to the ressure of the refrigerant for controlling t e capacity of the circuit interrupting means and arranged to control the amount of charge taken in' by said circulating means.

9. In a refrigeratin system in combination, a refrigerating e ement, a compressor for supplyin refrigerant to said element, a motor for riving said compressor, a safety device in the motor circuit, an auxiliary safety device for said motor circuit, and means operated in response to conditions within said 5 stem for inserting said auxiliary safety evice into the motor circuit.

In testimony whereof I hereto afiix my signature.

HARRY B. HULL. 

